The invention relates to an arrangement for transmitting check characters to selectable connector elements of a tester to which a unit under test can be connected, wherein the individual connector element is selected with the assistance of an address.
Units under test having a multitude of electronic components, for example, card modules, must be tested for freedom from error before being built into, for example, a data processing system. To that end, they are tested with the assistance of a tester which generates the test signals required for testing the card module and which checks the output signals emitted by the card module. It must thereby be guaranteed that the proper test signals are supplied to the unit under test at its connector elements. Since the unit under test is connected to the tester via plug-type connections, the tester must be constructed such that the proper test signals are transmitted via the contact elements of the tester allocated to the contact elements of the unit under test.
A respective address is permanently allocated to the connector elements, for example, terminal pins, in order to be able to supply the desired test signals to the individual contact elements or connector elements of the tester. When a test signal is to be transmitted over a specific connector element of the tester, then this connector element is addressed by the tester and the check character is then supplied to the addressed connector element. A check character can be evaluated with the assistance of a function code in order to produce the desired test signal. For example, whether the test signal which is developed from the check character is to have TTL level or ECL level, etc., can be determined with the assistance of the function code.
In order to transmit a specific test signal over a connector element of the tester, a word referred to below as the machine word must be evaluated in the tester, said machine word consisting of an address and a check character. Such a machine word was respectively necessary, thus, for each test signal to be transmitted over a connector element. Even when, for example, the same test signal is to be transmitted over a plurality of connector elements, a separate machine word had to be evaluated for each connector element because of the different addresses of the connector elements in the tester. The consequence was that a great number of machine words was necessary for testing a unit under test.